In medical applications, it is sometimes necessary to deliver fluid intravenously to a patient undergoing treatment. The fluid may be contained in a bag or other fluid reservoir, conveyed through a tube, and inserted into the patient's vein. At times, the amount of fluid conveyed to the patient must be controlled or regulated. In those instances where the fluid to the patient must be controlled, pumps have been used.
One pump is described in U.S. Pat. No. 4,559,038. This pump controls the delivery of fluid from the reservoir to the patient. In the '038 patent, the fluid is in a bag held in a container, or cassette, immediately adjacent to the pump. The pump controls the amount of fluid to the patient by physically pressuring the tube from the bag to the patient, and restricting the volume of fluid allowed to flow to the patient. The pump includes a pump mechanism which engages the tube and squeezes the tube against a pressure plate of the cassette to effect pumping of fluid.
It is also known to use the pump with a fluid reservoir that is remote, or separate from the pump. Typically, in a remote system, the fluid is contained in a bag and hung on a device separate from the pump. The bag has a tube extending from the bag, across a section of the pump, and then to the patient. Again, the pump controls the amount of fluid to the patient by mechanical pressure on the tube. A pressure plate mounted to the pump allows the pump mechanism to engage the tube to effect pumping.
In the past, certain types of pressure plates have been used to connect the pump to the tube. Because of reasons such as safety and cleanliness, the pressure plate is permanently attached to the tube. When the fluid reservoir is empty, or the treatment to the patient completed, the reservoir, tube, and pressure plate are all thrown away. Disposing of the pressure plate contributes to waste and expense. There is a need for systems and methods that allow reuse of the pressure plate. For reusable pressure plates, there is also a need for systems and methods that allow for selective detachment of the pressure plate from the pump, even during periods of nonuse.